TSA backscatter X-Ray scanners

[grantime]

Has anyone seen any real studies on amount of dose involved in these type of devices?  I personally don't have much faith in boilerplate statements about it being "minimal" or on other side "cancer causing".  I do admit more than a bit of concern with even a small dose each spread over really large population but I haven't seen any real data.

[co60slr]

Has anyone seen any real studies on amount of dose involved in these type of devices?  I personally don't have much faith in boilerplate statements about it being "minimal" or on other side "cancer causing".  I do admit more than a bit of concern with even a small dose each spread over really large population but I haven't seen any real data.

We all get on average about 20 mrem/month from naturally occurring background radiation.
Flying cross-country for four hours at 35,000 feet gives you about 4 mrem/flight.
The TSA scanner is "reported" to give the unlucky passenger a dose of less than 4 mrem (i.e., "less than the airline flight").

I don't think there's much to see here.   We all get radiation every day.   It rips through DNA.   People get cancer.   Was it caused by transuranics in concrete, background from space, occupational dose at work, etc?   Who knows.

Meanwhile, I personally would rather not find out at 35,000 feet that a woman on the plane has plastic explosives in her 44D size bra.   


Welcome to the 21st century.  Buckle up...it's likely to be a bumpy ride.

[Marlin]

"The Health Physics Society (HPS) reports that a person undergoing a backscatter scan receives approximately 0.05 μSv (or 0.005 mrems) of radiation; American Science and Engineering Inc. reports 0.09 μSv (0.009 mrems). At the high altitudes typical of commercial flights, naturally occurring cosmic radiation is considerably higher than at ground level. The radiation dose for a six hour flight is 20 μSv (2 mrems) - 200 to 400 times larger than a backscatter scan. According to US regulatory agencies, "1 mrem per year is a negligible dose of radiation, and 25 mrem per year from a single source is the upper limit of safe radiation exposure".[11]"

http://en.wikipedia.org/wiki/Backscatter_X-ray

[Frankie Love]

Something from our group...

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[grantime]

thanks

[JsonD13]

The problem with this isnt the whole body dose, its the potentially immense dose that you can get to your skin from this machine.  These machines are based upon an energy (~28 kev), that will not penetrate the whole body, but will penetrate the skin.  If you look at your probability of interaction at this energy, youll find that a whole lot more of these x-rays will hit your atoms than gammas at 1-2 MeV (or the high energy stuff you get thrown into on a flight). 

Now comes the tricky part.

Now when you compare organ dose to whole body dose you apply a weighting factor.  However to just report the whole body dose may not be the most correct thing to do since there can exist a threshold dose for some organs.  The question you have to ask is if you believe that the skin has a threshold dose.  I have not done much research to check this fact, but it seems to me that it probably does at some high level.

Really what John Hopkins physics lab did when they measured the dose rates this thing produces is used an ion chamber about a foot away from the machine.  You can apply correction factors for what you are measuring in the chamber accounting for the shielding that the chamber wall produces but nothing was said in the document (as far as I've read) that the machine was calibrated for the specific energy x-ray that these things produce (calibration with a Co-60 or Cs-137 source would not work here).  Lack of data in their report is what is causing the small group of scientists and doctors to petition the TSA.

Happy debating

Jason

[BetaAnt]

Why try to smuggle explosives onto the plane? Detonate in the security line or sit at the end of an active runway and use an RPG or equivalent. 

Face it the terrorists have won because the US will not do anything to offend profiled terrorists. 

What is the power gradient of the millimeter wave scanner and what is the associated danger of millimeter wave exposure? Just as radar techs are cautious around active units (microwave ovens), should TSA personnel be cautious around the millimeter wave generator (milliwave ovens)?

Where are all the Greenies demanding zero exposure from nuke plants? We are cooking passengers one at a time and TSA agents a shift at a time. There are too many unknowns. 

The fallacy of only 2% being scanned and groped (assaulted) is you are pegged every single time if you have an implant. That sux! 

[Homer S.]

For those of you who haven't seen this yet:

An alternative to body scanners at airports . . .
   

    The Israelis are developing an airport security device that eliminates the privacy concerns that come with full-body scanners at the airports.
   
    It's a booth you can step into that will not X-ray you, but will detonate any explosive device you may have on you. They see this as a win-win for everyone, with none of this crap about racial profiling. It also would eliminate the costs of a long and expensive trial.  Justice would be swift. Case closed!
   
    You're in the airport terminal and you hear a muffled explosion. Shortly thereafter an announcement comes over the PA system . . . "Attention standby passengers — we now have a seat available on flight

[RADBASTARD]

I would love to hear the truth on what the dose truly is in mr not some bs it's a little over background.That could mean the background at cherynoble???
I am going on a flight in a couple of weeks and im going to see if i can get a tld to wear in with me to see the true dose. Then we will know the truth.

Also I love the idea of those sob's blowing up in a booth.
no racial profiling,no muslim women in burques,no kids,no old ladies.
Just take care of business and blow the bombers up in a booth fair and equal justice,so the aclu and libs can stop crying about profiling

[HydroDave63]

This letter from UCSF raised some interesting issues:

http://docs.google.com/viewer?a=v&q=cache:RpteglBatgcJ:www.npr.org/assets/news/2010/05/17/concern.pdf+scanner+x-ray+letter&hl=en&gl=us&pid=bl&srcid=ADGEESi67LRsaEOQep8bd1s-23ZwuN9-J9DC-TfW0bhWurDD_NJHKdhywjLiU0gObaxcIxMgOE9dqVDK7uifQ3AJh5SN97T0qKlt9ZMJlX1W8PFYjti-bRXfcldJZ_qXOvM5lmK2LfCd&sig=AHIEtbRlHOhx7nKeoRNm20oUGiYHpjc9oQ

[jjack50]

Its hard to believe there is any skin dose or other risk if the whole body dose is as reported between 0.005 and 0.01 rem. I can't imagine that is significantly more than standing in front of the wall at Grand Central Station or next to many other granite walls for a reasonable amount of time. To delve into a discussion of energy levels and photon flux seems over kill at such a low exposure level.
An MIT document compares the exposure level to that of eating one banana. Seems an apt comparison to me.

[Jonesmp]

The backscatter radiation detectors use electrolytic activation of the electrons on Lithium at .28 kev.  there is a skin dose, but whole body is essentially negligible.  D=(6CEN)/R^2 with curie content based on amperage (they plug in) at a maximum of 20 amps AC, with my most conservative estimates, a whole body dose would be .03 mrem and a shallow dose of up to 9 mrem for a 60 second scan.  Again, those are VERY conservative calculations, and a dental X-ray gives you 15-50 mrem with a CT scan being 100-500 mrem.  As far as radiation, it's really nothing to worry about.

The average person in the United States by the current numbers gets 300-500 mrem/yr with 54% on average coming from radon alone (natural).